Within thirty days after the appointment of the members of the board of health in a general health district, they shall organize by selecting one of the members as president and another member as president pro tempore. The board shall appoint a health commissioner upon such terms, and for such period of time, not exceeding five years, as may be prescribed by the board. The person appointed as commissioner shall be a licensed physician, licensed dentist, a licensed veterinarian, licensed podiatrist, licensed chiropractor, or the holder of a master’s degree in public health or an equivalent master’s degree in a related health field as determined by the members of the board of health in a general health district. He shall be secretary of the board, and shall devote such time to the duties of his office as may be fixed by contract with the board. Notice of such appointment shall be filed with the director of health. The commissioner shall be the executive officer of the board and shall carry out all orders of the board and of the department of health. He shall be charged with the enforcement of all sanitary laws and regulations in the district. The commissioner shall keep the public informed in regard to all matters affecting the health of the district. When the commissioner is not a physician, the board shall provide for adequate medical direction of all personal health and nursing services by the employment of a licensed physician as medical director on either a full-time or part-time basis. The medical director shall be responsible to the board of health.